Microfluidic technology provides unique tools to perform biological analysis and chemical synthesis with precise control of concentrations, and tools to understand reaction products and investigate the fundamental science of transport at sub-micron scales. However, unlike customizable system technologies such as circuit electronics that can be designed and used with relatively accessible tools and uniform production infrastructure, microfluidics requires stringent manufacturing tolerances and faces practical issues (e.g., material restrictions, tight sealing). As microfluidic systems are being built and tested, it can be useful to be able to easily change the set-up of such a system without creating delays while manufacturing individual pieces for use as part of the system. Likewise, it can be beneficial for systems to be adaptable such that various components that measure different parameters can be quickly swapped in and out of the system, or combined as part of a single system, to expedite the analyses performed by the systems. Moreover, it can be beneficial to integrate sensors and actuators, e.g., optical probes and valves, in close proximity to a fluid path in order to perform more accurate analyses.
Numerous specialized and complex methods for fabrication have evolved for microfluidics systems, many of which can be developed only by highly skilled works in well-funded laboratories. Indeed, the commercial viability of many lab-on-a-chip diagnostic tools has been limited by the high capital cost of manufacturing the devices, especially at the minute (typically micrometer-scale) dimensional tolerances required. Further, even as manufacturing techniques for creating microfluidics systems evolve, existing techniques are typically best suited for small volume production. While it can often be desirable to have a microfluidic system that can be rapidly adjusted on the fly, this can be difficult to do while still maintaining accuracy and preventing incidents (e.g., leaking).
One manufacturing technique that has gained some traction in the microfluidic space is three-dimensional printing (e.g., additive manufacturing) because of its generally customizable nature. These techniques have led to modular system development, but typically only for small-scale production. This is at least because of the many limitations that can exist in three-dimensionally printed systems, such as: choice of materials, dimensional resolution including minimum feature size and surface roughness, and long-term dimensional stability (particularly when in contact with a fluid). Modularity places stringent requirements on accuracy, repeatability, interchangeability—essential criteria to enable rapid construction of systems from a component library, and for maintenance of tight seals between modules, particularly if the system is reconfigurable. Other known manufacturing techniques, such as injection-molding, are not preferred because of the high tooling costs for producing a large number of identical units.
Accordingly, there is a need to be able to create microfluidic systems at a high volume while still meeting the stringent requirements related to manufacturing tolerances and the like so that the systems may perform accurately and without incident (e.g., leaking). There is a further need to be able to allow for microfluidic systems to be highly customizable and reconfigurable even when at least portions of the systems are mass-produced. Improved methods for forming a microfluidic path, and for passing a fluid through a microfluidic path, are also desired.